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Malaria Journal Mar 2024Adults infected with Plasmodium spp. in endemic areas need to be re-evaluated in light of global malaria elimination goals. They potentially undermine malaria...
BACKGROUND
Adults infected with Plasmodium spp. in endemic areas need to be re-evaluated in light of global malaria elimination goals. They potentially undermine malaria interventions but remain an overlooked aspect of public health strategies.
METHODS
This study aimed to estimate the prevalence of Plasmodium spp. infections, to identify underlying parasite species, and to assess predicting factors among adults residing in an endemic area from the Democratic Republic of Congo (DRC). A community-based cross-sectional survey in subjects aged 18 years and above was therefore carried out. Study participants were interviewed using a standard questionnaire and tested for Plasmodium spp. using a rapid diagnostic test and a nested polymerase chain reaction assay. Logistic regression models were fitted to assess the effect of potential predictive factors for infections with different Plasmodium spp.
RESULTS
Overall, 420 adults with an estimated prevalence of Plasmodium spp. infections of 60.2% [95% CI 55.5; 64.8] were included. Non-falciparum species infected 26.2% [95% CI 22.2; 30.5] of the study population. Among infected participants, three parasite species were identified, including Plasmodium falciparum (88.5%), Plasmodium malariae (39.9%), and Plasmodium ovale (7.5%) but no Plasmodium vivax. Mixed species accounted for 42.3% of infections while single-species infections predominated with P. falciparum (56.5%) among infected participants. All infected participants were asymptomatic at the time of the survey. Adults belonging to the "most economically disadvantaged" households had increased risks of infections with any Plasmodium spp. (adjusted odds ratio, aOR = 2.87 [95% CI 1.66, 20.07]; p < 0.001), compared to those from the "less economically disadvantaged" households. Conversely, each 1 year increase in age reduced the risk of infections with any Plasmodium spp. (aOR = 0.99 [95% CI 0.97, 0.99]; p = 0.048). Specifically for non-falciparum spp., males had increased risks of infection than females (aOR = 1.83 [95% CI 1.13, 2.96]; p = 0.014).
CONCLUSION
Adults infected with malaria constitute a potentially important latent reservoir for the transmission of the disease in the study setting. They should specifically be taken into account in public health measures and translational research.
Topics: Male; Adult; Female; Humans; Democratic Republic of the Congo; Cross-Sectional Studies; Malaria; Malaria, Falciparum; Plasmodium falciparum; Plasmodium malariae; Prevalence
PubMed: 38500094
DOI: 10.1186/s12936-024-04881-7 -
Prevalence of Falciparum and non-Falciparum Malaria in the 2014-15 Rwanda Demographic Health Survey.MedRxiv : the Preprint Server For... Jan 2024Malaria remains a major cause of morbidity in sub-Saharan Africa. Undetected asymptomatic falciparum malaria results in a large transmission reservoir and there is...
BACKGROUND
Malaria remains a major cause of morbidity in sub-Saharan Africa. Undetected asymptomatic falciparum malaria results in a large transmission reservoir and there is evidence of increasing non-falciparum malaria as malaria is controlled in Africa, both resulting in challenges for malaria control programs.
METHODS
We performed quantitative real time PCR for 4 malaria species in 4,596 individuals from the 2014-2015 Rwanda Demographic Health Survey. Bivariate models were used to determine species-specific associations with risk factors.
RESULTS
Asymptomatic falciparum malaria, , and infection had broad spatial distribution across Rwanda. infection was rare. Overall infection prevalence was 23.6% (95%CI [21.7%, 26.0%]), with falciparum and non-falciparum at 17.6% [15.9%, 19.0%] and 8.3% [7.0%, 10.0%], respectively. Parasitemias tended to be low and mixed species infections were common, especially where malaria transmission was the highest. Falciparum infection was associated with socio-econiomic status, rural residence and low altitude. Few risk factors were associated with non-falciparum malaria.
CONCLUSIONS
Asymptomatic falciparum malaria and non-falciparum malaria are common and widely distributed across Rwanda. Continued molecular monitoring of is needed to monitor these threats to malaria control in Africa.
PubMed: 38260604
DOI: 10.1101/2024.01.09.24301054 -
PloS One 2024Wildlife trafficking creates favorable scenarios for intra- and inter-specific interactions that can lead to parasite spread and disease emergence. Among the fauna...
Wildlife trafficking creates favorable scenarios for intra- and inter-specific interactions that can lead to parasite spread and disease emergence. Among the fauna affected by this activity, primates are relevant due to their potential to acquire and share zoonoses - infections caused by parasites that can spread between humans and other animals. Though it is known that most primate parasites can affect multiple hosts and that many are zoonotic, comparative studies across different contexts for animal-human interactions are scarce. We conducted a multi-parasite screening targeting the detection of zoonotic infections in wild-caught monkeys in nine Peruvian cities across three contexts: captivity (zoos and rescue centers, n = 187); pet (households, n = 69); and trade (trafficked or recently confiscated, n = 132). We detected 32 parasite taxa including mycobacteria, simian foamyvirus, bacteria, helminths, and protozoa. Monkeys in the trade context had the highest prevalence of hemoparasites (including Plasmodium malariae/brasilianum, Trypanosoma cruzi, and microfilaria) and enteric helminths and protozoa were less common in pet monkeys. However, parasite communities showed overall low variation between the three contexts. Parasite richness (PR) was best explained by host genus and the city where the animal was sampled. Squirrel (genus Saimiri) and wooly (genus Lagothrix) monkeys had the highest PR, which was ~2.2 times the PR found in tufted capuchins (genus Sapajus) and tamarins (genus Saguinus/Leontocebus) in a multivariable model adjusted for context, sex, and age. Our findings illustrate that the threats of wildlife trafficking to One Health encompass exposure to multiple zoonotic parasites well-known to cause disease in humans, monkeys, and other species. We demonstrate these threats continue beyond the markets where wildlife is initially sold; monkeys trafficked for the pet market remain a reservoir for and contribute to the translocation of zoonotic parasites to households and other captive facilities where contact with humans is frequent. Our results have practical applications for the healthcare of rescued monkeys and call for urgent action against wildlife trafficking and ownership of monkeys as pets.
Topics: Humans; Animals; Peru; Prevalence; Zoonoses; Animals, Wild; Plasmodium; Parasites; Haplorhini; Saguinus; Helminths
PubMed: 38324542
DOI: 10.1371/journal.pone.0287893 -
Frontiers in Public Health 2023The provincial malaria diagnosis reference laboratories review and assess malaria cases diagnosed in health facilities for supporting the malaria elimination efforts and...
INTRODUCTION
The provincial malaria diagnosis reference laboratories review and assess malaria cases diagnosed in health facilities for supporting the malaria elimination efforts and preventing re-transmission of imported malaria. The study aimed to evaluate the detection capability of malaria diagnosis in China from 2014 to 2021.
METHODS
Data on malaria cases reported in the provincial-level administrative divisions (PLADs) of Anhui, Henan, Hubei, Guangxi, and Zhejiang from 2014 to 2021 were collected and analyzed.
RESULTS
In total, 5,770 malaria cases were reported from 2014 to 2021, and 99.05% (5,715/5,770) were submitted to the provincial malaria diagnosis reference laboratories. The median time between malaria cases being reported and the samples being received by reference laboratories was 6 days (Interquartile range, IQR:3-12 days) from 2017 to 2021. Diagnosis of 5,680 samples in the laboratory were confirmed by provincial reference laboratories, including 3,970 cases of , 414 of , 1,055 of , 158 of , 1 of , and 82 of mixed infections. species of 5,141 confirmed cases were consistent with the initial diagnosis, with a species accuracy rate of 90.53% (5,141/5,679). The accuracy of diagnosis in health facilities was higher than that of non-falciparum species. The inconsistency between microscopy and nested polymerase chain reaction (nPCR) results of confirmatory diagnosis was mainly in malaria-positive versus malaria-negative cases, as well as in mixed versus single infection cases.
CONCLUSION
The provincial malaria diagnosis reference laboratories have played an important role in ensuring the accuracy and reliability of diagnosis in health facilities. However, the results of this study imply that capacity training for the identification of species in health facilities is warranted.
Topics: Humans; Laboratories; Reproducibility of Results; China; Malaria; Plasmodium
PubMed: 37841716
DOI: 10.3389/fpubh.2023.1243642 -
Mikrobiyoloji Bulteni Jul 2023Malaria is a serious, contagious infection caused by single-celled parasites. About 200 species of Plasmodium have been described that can cause infection in...
Malaria is a serious, contagious infection caused by single-celled parasites. About 200 species of Plasmodium have been described that can cause infection in vertebrates. Five different species of Plasmodium are known to cause infection in humans to date. Infection with more than one type of pathogen is called coinfection. This type of infections can be caused by different species of the same genus, as well as by different species. Malaria coinfections are mostly caused by the combination of Plasmodium vivax and Plasmodium falciparum. In this study, a case of malaria admitted to the hospital and diagnosed was presented. Thin smear blood preparations were prepared from the peripheral blood of a 54 year-old Republic of Türkiye citizen male patient who applied to the emergency department with fever and chills. The preparations were stained with Giemsa and examined under a microscope with a x 100 objective, and trophozoite and gametocyte forms belonging to Plasmodium genus were determined. As a result of probe-based quantitative real-time polymerase chain reaction (qRt-PCR) study with primers specific to Plasmodium vivax, Plasmodium malariae, Plasmodium falciparum, Plasmodium ovale and Plasmodium knowlesi for definitive species identification, co-infection of P.vivax, P.falciparum, P.ovale and P.knowlesi was detected in the patient. In addition, it was proved that our patient was infected with four different species by conventional PCR study in which five species were studied and then by DNA sequence analysis. On the fourth day of artemether-lumefantrine treatment, the patient's fever response was observed and the trophozoite forms disappeared from the third day in the daily peripheral smear follow-up. Since P.vivax and P.ovale species were also detected after species determination by molecular methods, primaquine 1 x 30 mg tablet was added to the existing drugs for the treatment of hypnozoite forms of the parasite. In recent years, there has been an increase in malaria imported cases, especially after visits to African countries. Such rare cases of malaria coinfection may be encountered during visits to geographies located at the intersection of endemic regions. According to the data of the World Health Organization, maximum attention should be paid to the prevention and prophylaxis protocols from vectors, especially in travels to countries with the highest mortality and morbidity. In co-infection cases similar to our patient, for tertian malaria and tertiary ovale malaria, hypnozoid therapy should not be overlooked. When the insecticide-resistant vectors and drug-resistant Plasmodium strains encountered in recent years are evaluated as a whole, there is a need to develop more effective strategies in the fight against malaria. In addition to microscopic examination, which is accepted as the gold standard, we believe that evaluating molecular studies together in diagnosis is extremely important for the treatment process when hypnozoite periods are considered.
Topics: Animals; Male; Humans; Middle Aged; Coinfection; Antimalarials; Cameroon; Artemether; Artemether, Lumefantrine Drug Combination; Malaria; Malaria, Vivax; Plasmodium; Plasmodium falciparum; Plasmodium vivax; Real-Time Polymerase Chain Reaction
PubMed: 37462313
DOI: 10.5578/mb.20239942 -
Malaria Journal Jan 2024Malaria remains a major public health problem in the Republic of Congo, with Plasmodium falciparum being the deadliest species of Plasmodium in humans. Vector...
BACKGROUND
Malaria remains a major public health problem in the Republic of Congo, with Plasmodium falciparum being the deadliest species of Plasmodium in humans. Vector transmission of malaria is poorly studied in the country and no previous report compared rural and urban data. This study aimed to determine the Anopheles fauna and the entomological indices of malaria transmission in the rural and urban areas in the south of Brazzaville, and beyond.
METHODS
Indoor household mosquitoes capture using electric aspirator was performed in rural and urban areas during raining and dry seasons in 2021. The identification of Anopheles species was done using binocular magnifier and nested-PCR. TaqMan and nested-PCR were used to detect the Plasmodium species in the head/thorax and abdomens of Anopheles. Some entomological indices including the sporozoite infection rate, the entomological inoculation rate and the man biting rate were estimated.
RESULTS
A total of 699 Anopheles mosquitoes were collected: Anopheles gambiae sensu lato (s.l.) (90.7%), Anopheles funestus s.l. (6.9%), and Anopheles moucheti (2.4%). Three species of An. gambiae s.l. were identified including Anopheles gambiae sensu stricto (78.9%), Anopheles coluzzii (15.4%) and Anopheles arabiensis (5.7%). The overall sporozoite infection rate was 22.3% with a predominance of Plasmodium falciparum, followed by Plasmodium malariae and Plasmodium ovale. Anopheles aggressiveness rate was higher in households from rural area (1.1 bites/night) compared to that from urban area (0.8 ib/p/n). The overall entomological inoculation rate was 0.13 ib/p/n. This index was 0.17 ib/p/n and 0.092 ib/p/n in rural and in urban area, respectively, and was similar during the dry (0.18 ib/p/n) and rainy (0.14 ib/p/n) seasons.
CONCLUSION
These findings highlight that malaria transmission remains high in rural and urban area in the south of Republic of Congo despite the ongoing control efforts, thereby indicating the need for more robust interventions.
Topics: Animals; Humans; Malaria, Falciparum; Congo; Mosquito Vectors; Plasmodium; Plasmodium falciparum; Malaria; Bites and Stings; Sporozoites; Anopheles
PubMed: 38229020
DOI: 10.1186/s12936-023-04823-9 -
PLOS Global Public Health 2024Malaria is endemic in the Central region of Ghana, however, the ecological and the seasonal variations of Plasmodium population structure and the intensity of malaria...
Malaria is endemic in the Central region of Ghana, however, the ecological and the seasonal variations of Plasmodium population structure and the intensity of malaria transmission in multiple sites in the region have not been explored. In this cross-sectional study, five districts in the region were involved. The districts were Agona Swedru, Assin Central and Gomoa East (representing the forest zone) and Abura-Asebu-Kwamankese and Cape Coast representing the coastal zone. Systematically, blood samples were collected from patients with malaria. The malaria status was screened with a rapid diagnostic test (RDT) kit (CareStart manufactured by Access Bio in Somerset, USA) and the positive ones confirmed microscopically. Approximately, 200 μL of blood was used to prepare four dried blood spots of 50μL from each microscopy positive sample. The Plasmodium genome was sequenced at the Malaria Genome Laboratory (MGL) of Wellcome Sanger Institute (WSI), Hinxton, UK. The single nucleotide polymorphisms (SNPs) in the parasite mitochondria (PfMIT:270) core genome aided the species identification of Plasmodium. Subsequently, the complexity of infection (COI) was determined using the complexity of infection likelihood (COIL) computational analysis. In all, 566 microscopy positive samples were sequenced. Of this number, Plasmodium genome was detected in 522 (92.2%). However, whole genome sequencing was successful in 409/522 (72.3%) samples. In total, 516/522 (98.8%) of the samples contained P. falciparum mono-infection while the rest (1.2%) were either P. falciparum/P. ovale (Pf/Po) (n = 4, 0.8%) or P. falciparum/P. malariae/P. vivax (Pf/Pm/Pv) mixed-infection (n = 2, 0.4%). All the four Pf/Po infections were identified in samples from the Assin Central municipality whilst the two Pf/Pm/Pv triple infections were identified in Abura-Asebu-Kwamankese district and Cape Coast metropolis. Analysis of the 409 successfully sequenced genome yielded between 1-6 P. falciparum clones per individual infection. The overall mean COI was 1.78±0.92 (95% CI: 1.55-2.00). Among the study districts, the differences in the mean COI between ecological zones (p = 0.0681) and seasons (p = 0.8034) were not significant. However, regression analysis indicated that the transmission of malaria was more than twice among study participants aged 15-19 years (OR = 2.16, p = 0.017) and almost twice among participants aged over 60 years (OR = 1.91, p = 0.021) compared to participants between 20-59 years. Between genders, mean COI was similar except in Gomoa East where females recorded higher values. In conclusion, the study reported, for the first time, P. vivax in Ghana. Additionally, intense malaria transmission was found to be higher in the 15-19 and > 60 years, compared to other age groups. Therefore, active surveillance for P. vivax in Ghana and enhanced malaria control measures in the 15-19 year group years and those over 60 years are recommended.
PubMed: 38236793
DOI: 10.1371/journal.pgph.0002718 -
Acta Parasitologica Mar 2024Malaria remains a major public health issue in the world despite a decline in the disease burden. However, though symptomatic malaria is diagnosed and treated,...
BACKGROUND
Malaria remains a major public health issue in the world despite a decline in the disease burden. However, though symptomatic malaria is diagnosed and treated, asymptomatic infections remain poorly known and support transmission. This study assessed the prevalence of symptomatic and asymptomatic Plasmodium spp. infections in three areas in Gabon to monitor and evaluate the impact of malaria.
METHODS AND RESULTS
A cross-sectional study was conducted in three areas of Gabon. Febrile and afebrile children aged 6 months to 15 years were included in this study. Malaria prevalence was determined by microscopy of and using rapid diagnostic test (RDT). Plasmodium spp. species were identified by PCR according to the Snounou method. The data were recorded in Excel, and the statistical analyses were performed using the software R version R 64 × 3.5.0. A total of 2381(333 asymptomatic and 107 symptomatic) children were included. The overall prevalence of malaria was 40% (952/2381), with the majority (77% symptomatic and 98% asymptomatic) of infections caused by Plasmodium falciparum. A high prevalence of malaria was found in infected children in rural and semi-rural areas. In these two areas, a higher prevalence of Plasmodium malariae was observed in asymptomatic. Furthermore, mixed infections were more prevalent in asymptomatic children than in symptomatic.
CONCLUSION
This study showed that the prevalence of Plasmodium spp. infection varied according to the regions. The main species was Plasmodium falciparum, but in asymptomatic children the prevalence of Plasmodium malariae was high in rural areas. To help fight malaria more effectively asymptomatic infections should be taken into account and treated.
Topics: Humans; Gabon; Child; Child, Preschool; Prevalence; Cross-Sectional Studies; Adolescent; Infant; Rural Population; Male; Female; Malaria; Urban Population; Asymptomatic Infections; Plasmodium; Polymerase Chain Reaction; Malaria, Falciparum; Plasmodium falciparum
PubMed: 38194048
DOI: 10.1007/s11686-023-00783-x -
Frontiers in Immunology 2024Human malaria, caused by five Plasmodium species (, and ), remains a significant global health burden. While most interventions target , the species associated with high...
Identification of conserved cross-species B-cell linear epitopes in human malaria: a subtractive proteomics and immuno-informatics approach targeting merozoite stage proteins.
Human malaria, caused by five Plasmodium species (, and ), remains a significant global health burden. While most interventions target , the species associated with high mortality rates and severe clinical symptoms, non-falciparum species exhibit different transmission dynamics, remain hugely neglected, and pose a significant challenge to malaria elimination efforts. Recent studies have reported the presence of antigens associated with cross-protective immunity, which can potentially disrupt the transmission of various Plasmodium species. With the sequencing of the Plasmodium genome and the development of immunoinformatic tools, in this study, we sought to exploit the evolutionary history of Plasmodium species to identify conserved cross-species B-cell linear epitopes in merozoite proteins. We retrieved Plasmodium proteomes associated with human malaria and applied a subtractive proteomics approach focusing on merozoite stage proteins. Bepipred 2.0 and Epidope were used to predict B-cell linear epitopes using as the reference species. The predictions were further compared against human and non-falciparum databases and their antigenicity, toxicity, and allergenicity assessed. Subsequently, epitope conservation was carried out using locally sequenced isolates from a malaria-endemic region in western Kenya (n=27) and Kenyan isolates from MalariaGEN version 6 (n=131). Finally, physiochemical characteristics and tertiary structure of the B-cell linear epitopes were determined. The analysis revealed eight epitopes that showed high similarity (70-100%) between falciparum and non-falciparum species. These epitopes were highly conserved when assessed across local isolates and those from the MalariaGEN database and showed desirable physiochemical properties. Our results show the presence of conserved cross-species B-cell linear epitopes that could aid in targeting multiple Plasmodium species. Nevertheless, validating their efficacy and experimentally is essential.
Topics: Animals; Humans; Merozoites; Epitopes, B-Lymphocyte; Kenya; Proteomics; Plasmodium falciparum; Plasmodium vivax; Malaria; Malaria, Falciparum; Plasmodium; Malaria, Vivax
PubMed: 38404581
DOI: 10.3389/fimmu.2024.1352618 -
Open Forum Infectious Diseases Nov 2023Scarcity of annotated image data sets of thin blood smears makes expert-level differentiation among species challenging. Here, we aimed to establish a deep learning...
BACKGROUND
Scarcity of annotated image data sets of thin blood smears makes expert-level differentiation among species challenging. Here, we aimed to establish a deep learning algorithm for identifying and classifying malaria parasites in thin blood smears and evaluate its performance and clinical prospect.
METHODS
You Only Look Once v7 was used as the backbone network for training the artificial intelligence algorithm model. The training, validation, and test sets for each malaria parasite category were randomly selected. A comprehensive analysis was performed on 12 708 thin blood smear images of various infective stages of 12 546 malaria parasites, including , , , , , and . Peripheral blood samples were obtained from 380 patients diagnosed with malaria. Additionally, blood samples from monkeys diagnosed with malaria were used to analyze . The accuracy for detecting -infected blood cells was assessed through various evaluation metrics.
RESULTS
The total time to identify 1116 malaria parasites was 13 seconds, with an average analysis time of 0.01 seconds for each parasite in the test set. The average precision was 0.902, with a recall and precision of infected erythrocytes of 96.0% and 94.9%, respectively. Sensitivity and specificity exceeded 96.8% and 99.3%, with an area under the receiver operating characteristic curve >0.999. The highest sensitivity (97.8%) and specificity (99.8%) were observed for trophozoites and merozoites.
CONCLUSIONS
The algorithm can help facilitate the clinical and morphologic examination of malaria parasites.
PubMed: 37937045
DOI: 10.1093/ofid/ofad469